It's the worst kind of ponzi scheme. It forces the poor to pay for the retirement of the wealthier class.
A blue collar fella who works from 18-65 typically dies younger. So he worked 47 years and got, say, 5 years of retirement. A white collar fella more typically works 22-60 and then lives longer, so he worked 38 years and gets, say, 20 years of retirement. It's a huge transfer of wealth, and that's not even mentioning that it might not be there when I retire.
Almost everybody is on the same page about SS#, but we can't get any meaningful change.